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3 years ago

2. Solve the following system. Show all your work. {3x - 2y + 2z = 30 {-x + 3y - 4z = -33 {2x - 4y + 3z = 42

1 answer:

6 0

From the system of equations, we have 3 unknowns and 3 equations. Therefore, it can be solved.

3x - 2y + 2z = 30 (1)
-x + 3y - 4z = -33 (2)
2x - 4y + 3z = 42 (3)

We can write equation 2 x as a function of y and z and substitute the new equation to the other equations.
x =3y - 4z + 33 (2)

3 (3y - 4z + 3) - 2y + 2z = 30 (1)
2 (3y - 4z + 3) - 4y + 3z = 42 (3)

We simplify and solve the equations and we get values,

x = 4
y = -7
z = 2

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Expand 4x(7x-11) For maths Help please

harina [27]

Answer:

$28x^2-44x$

Step-by-step explanation:

Use the distributive property.

$4x * 7x = 28x^2$

$4x * (-11) = -44x$

We will get $28x^2-44x$

Hope this helps!

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3 years ago

Marathon runner covered the whole distance in 4 hours running at a constant speed of 8.1 km per hour. How long would it take him

katen-ka-za [31]

Answer: it will take him 4.5 hours to cover same distance

Step-by-step explanation:

Marathon runner covered the whole distance in 4 hours running at a constant speed of 8.1 km per hour.

Speed = distance / time

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Therefore, distance covered by the marathon runner in in 4 hours, running at a speed of 8.1 km per hour is

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At 7.2 km per hour, the time it would take him to cover the same distance would be

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8 0

3 years ago

Find the coordinates of the point three tenths of the way from A(-4, -8) to B(11, 7)

Leviafan [203]

let's first off take a peek at those values.

let's say the point with those coordinates is point C, so C is 3/10 of the way from A to B.

meaning, we take the segment AB and cut it in 10 equal pieces, AC takes 3 pieces, and CB takes 7 pieces, namely AC and CB are at a 3:7 ratio.

$\bf ~~~~~~~~~~~~\textit{internal division of a line segment}
\\\\\\
A(-4,-8)\qquad B(11,7)\qquad
\qquad \stackrel{\textit{ratio from A to B}}{3:7}
\\\\\\
\cfrac{A\underline{C}}{\underline{C} B} = \cfrac{3}{7}\implies \cfrac{A}{B} = \cfrac{3}{7}\implies 7A=3B\implies 7(-4,-8)=3(11,7)\\\\[-0.35em]
~\dotfill\\\\
C=\left(\frac{\textit{sum of "x" values}}{\textit{sum of ratios}}\quad ,\quad \frac{\textit{sum of "y" values}}{\textit{sum of ratios}}\right)\\\\[-0.35em]
~\dotfill$

$\bf C=\left(\cfrac{(7\cdot -4)+(3\cdot 11)}{3+7}\quad ,\quad \cfrac{(7\cdot -8)+(3\cdot 7)}{3+7}\right)
\\\\\\
C=\left( \cfrac{-28+33}{10}~~,~~\cfrac{-56+21}{10} \right)\implies C=\left( \cfrac{5}{10}~~,~~\cfrac{-35}{10} \right)
\\\\[-0.35em]
\rule{34em}{0.25pt}\\\\
~\hfill C=\left( \frac{1}{2}~,~-\frac{7}{2} \right)~\hfill$

4 0

3 years ago

A sale girl receive a 5% commission on all she self. how much she has to sell to receive $15

ivann1987 [24]

Answer:

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Step-by-step explanation:

Sales x .05 commission = $15

sales=$15/.05

sales = 300

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3 years ago

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Alex787 [66]

Answer:

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3 years ago